Support to set a Distinct ID like Umami and set user name instead of random name

[Enjer]

Support to set a Distinct ID field so that when first identifying user it will not create a new user.
Current rybbit v2.1.2 creating a new user breaks the same user into 2 users when first identfiying a user.

And Distinct ID allows you to associate sessions and actions with a single user across multiple devices.

[goldflag]

i'm adding support for this very very soon